In situ mechanical characterization of a sample strain

A method of measuring a stress-strain curve in a sample, the method comprising:

• providing a structure including a first movable island supported by a first beam, a second movable island supported by a second beam, and a gap therebetween connected by the sample,
• the sample comprising an initial length;
• moving the second movable island with a defined displacement;
• determining a displacement of the first movable island based on moving the second movable island;
• calculating a difference between the displacement of the first movable island and the defined displacement of the second movable island based on moving the second movable island;
• determining an applied strain in the sample based on the difference divided by the initial length of the sample;
• calculating a force on the sample based on the displacement of the first movable island;
• calculating a stress on the sample based on the force;
• and
• determining the stress-strain curve of the sample by plotting the calculated stress against the applied strain,
• wherein providing a sample comprises:
• providing a sample in a liquid environment.

An apparatus for performing a displacement-controlled tensile test of a sample, the apparatus comprising:

• a first movable island supported by a first supporting beam having a first defined stiffness;
• and
• a second movable island supported by a second supporting beam having a second defined stiffness,
• the first moveable island and the second moveable island defining a junction therebetween having an initial length, and
• wherein a structure including a first movable island supported by a first beam, a second movable island supported by a second beam, and a gap therebetween connected by the sample is developed based on a nanofabricated polymeric structure using two-photon polymerization,
• wherein the first moveable island and the second moveable island are attached to an optically transparent substrate.